It is estimated that as many as 80% of women diagnosed with breast cancer may be eligible for breast cancer conservation (BCT) therapy. Numerous clinical trials have demonstrated that survival rates are increased if surgical removal of the tumor (lumpectomy) is followed by radiation therapy. Whole-breast external beam fractionated radiation therapy, often coupled with a boost dose to the tumor region, is now the clinically accepted standard-of-care.
Despite the high indication rate for cancer conservation therapy, many women still opt for mastectomy. This is partly due to the inconvenience of the fractionated treatment regimen which may last up to six weeks. The associated time commitment and logistical difficulties associated with daily travel may discourage a number of women from choosing cancer conservation therapy.
Accordingly, to significantly reduce the cost of treatment in general and encourage more patients to adopt cancer conservation therapy, there is a need for radiation treatment systems that require less capital equipment and infrastructure costs associated with building new treatment center closer to patients' residence. There is also a need for radiation therapy that requires reduced number of treatment fractions. Research into accelerated partial breast irradiation using interventional techniques such as MammoSite® has shown some promise. This has spurred encouraging investigations into hypo-fractionation using external beams such as intensity-modulated radiation therapy (IMRT).